1. Field of the Invention
This invention relates to a semiconductor ring laser apparatus which comprises a semiconductor laser element and a ring-formed resonator having a ring-formed optical path provided outside the element so as to form a ring laser oscillator.
2. Description of the Prior Art
A semiconductor laser element, as compared with a gas laser or the like, has the advantages of very small size, light weight, low consumption of electric power, high efficiency, low cost, as well as other advantages. Accordingly, the semiconductor laser element has recently begun to be used for optical communication, a laser printer, a video disc and others.
However, in the field of a ring laser gyroscope apparatus serving as an angular speed detector used in an inertial navigation apparatus for an aircraft or the like, a helium neon laser has held an unrivalled position and a semiconductor laser element has not heretofore been used. The reason is that a conventional semiconductor laser element is of the type that a waveguide in the crystal structure thereof is provided which makes a right angle to a cleavage plane of the crystal structure so that the cleavage plane serves as a mirror, and the wave guide extending between the front and rear parallel cleavage planes is formed to become a Fabry-Perot type optical resonator to effect laser oscillation. Consequently, even when a ring-formed optical path is provided outside that element, a ring-formed oscillator cannot be made and thus highly sensitive angular speed detection cannot be obtained.